Photographic materials

ABSTRACT

Photographic silver halide emulsions are spectrally sensitized with the combination of complex merocyanine dye, sulfonated polynuclear aromatic compound and reducing agent.

United States Patent Hiller [54] PHOTOGRAPHIC MATERIALS [72] Inventor: Gary L. Hiller, Rochester, N.Y.

[73] Assignee: Eastman Kodak Company, Rochester,

[22] Filed: Oct. 21, 1968 21 Appl.No.: 769,393

[52] U.S.Cl ..96/123,96/107,96/126 [51] InLCl ..G03cl/l0 [58] FieldofSearch ..96/104,127, 126,107, 95, 96/94 [56] References Cited UNITED STATES PATENTS 3,442,649 5/1969 Rasch et a1. ..96/94 2,503,776 4/1950 Sprague ..96/ 106 2,947,630 8/1960 Jones ..96/l04 2,961,318 11/1960 Jones ..96/104 Mar. 14, 1972 Primary Examiner-William D. Martin Assistant ExaminerWilliam R. Trenor Attorney-W. H. J. Kline, J. R. Frederick and O. H. Webster [57] ABSTRACT Photographic silver halide emulsions are spectrally sensitized with the combination of complex merocyanine dye, sulfonated polynuclear aromatic compound and reducing agent.

9 Claims, No Drawings PHOTOGRAPHIC MATERIALS This invention relates to novel photographic materials, and more particularly to spectrally sensitized photographic silver halide emulsions.

The spectral sensitization of photographic silver halide emulsions with supersensitizing combinations comprising various methine dyes with sulfonated organic compounds has been described previously, such as in U.S. Pat. Nos. 2,875,058; 2,933,390; 2,945,762; 2,947,630, and 2,961,318. When photographic silver halide emulsions are spectrally sensitized with complex merocyanine dyes, an undesirable reduction in the blue sensitivity of the emulsion results. While the addition of sulfonated polynuclear organic compounds increases the blue speed of emulsions containing complex merocyanine dyes, it would be highly desirable to provide emulsions containing complex merocyanine dyes which have even higher inherent blue speeds than are obtained with a combination of sulfonated polynuclear organic compound and complex merocyanine dye.

One object of this invention is to provide novel spectral sensitizing combinations for photographic silver halide emulsions.

Another object of this invention is to provide photographic silver halide emulsions containing complex merocyanine dyes which have good speed when exposed to blue radiation.

Other objects of this invention will be apparent from the disclosure herein and the appended claims.

In accordance with this invention, photographic silver halide emulsions are spectrally sensitized with the combination of complex merocyanine dye, sulfonated polynuclear organic supersensitizer and, a sufficient amount of a silver halide reducing agent to effectively increase the blue speed of the emulsion. It has been found that utilization of sulfonated polynuclear organic supersensitizer in combination with reducing agent materially increases the response to blue radiation (about 350 to 500 nm.) of silver halide emulsions spectrally sensitized with complex merocyanine dyes, This result is particularly surprising in view of the fact that the use of reducing agent in photographic silver halide emulsions containing sulfonated organic supersensitizer and various classes of methine dyes fails to result in any substantial increase in the blue speed of the emulsion. It could not have been foreseen that the combination of reducing agent and sulfonated polynuclear supersensitizer would in some manner coact to substantially enhance the blue speed of emulsions spectrally sensitized with complex merocyanine dye.

As used herein and in the appended claims, the term complex merocyanine dye refers to methine dyes having three fiveto six-membered nitrogen containing heterocyclic nuclei joined at carbon atoms thereof by a double bond or a methine (preferably dimethine) linkage, one terminal nucleus being a basic heterocyclic nucleus of the type used in cyanine dyes, and the other two nuclei being acidic ketomethylene heterocyclic nuclei of the type used in merocyanine dyes, said dye having a amidic chromophoric system. See The Theory of the Photographic Process by Mees and James, third edition, page 201 (1966), The MacMillan Company, New York.

The complex merocyanine dyes that are preferred in practicing this invention are those represented by the following formula:

I. l --z O=CNR2 dichlorobenzimidazole,

isopropyl, butyl, hexyl, cyclohexyl, decyl, dodecyl, etc., and substituted alkyl groups (preferably a substituted lower alkyl containing from one to four carbon atoms), such as a hydroxyalkyl group, e.g., B-hydroxy-ethyl, m-hydroxybutyl, etc., an alkoxyalkyl group, e.g., B-methoxyethyl, w-butoxybutyl, etc., a carboxyalkyl group, e.g., B-carboxyethyl, w-carboxybutyl, etc.; a sulfoalkyl group, e.g., B-sulfoethyl, w-sulfobutyl, etc., a sulfatoalkyl group, e.g., ,B-sulfatoethyl, w-sulfatobutyl, etc., an acyloxyalkyl group, e.g., ,B-acetoxyethyl, v-acetoxypropyl, wbutyryloxybutyl, etc., an alkoxycarbonylalkyl group, e.g., B- methoxycarbonylethyl, w-ethoxycarbonylbutyl, etc., or an aralkyl group, e.g., benzyl, phenethyl, etc., or, an aryl group, e.g., phenyl, tolyl, naphthyl, methoxyphenyl, chlorophenyl, etc.; R represents an alkyl group containing from one to four carbon atoms, e.g., methyl, butyl, etc., or an aryl group, e.g., phenyl, tolyl, chlorophenyl, methoxyphenyl, naphthyl, etc.; Z represents the nonmetallic atoms necessary to complete a fiveto six-membered heterocyclic nucleus, which nucleus may contain a second hetero atom such as oxygen, sulfur, selenium or nitrogen, such as the following nuclei: a thiazole nucleus, e.g., thiazole, 4-methylthiazole, 4-phenylthiazole, 5- methylthiazole, S-phenylthiazole, 4,5-dimethylthiazole, 4,5- diphenylthiazole, 4-(2-thienyl)thiazole, benzothiazole, 4- chlorobenzothiazole, 5-chl0robenzothiazole, 6- chlorobenzothiazole, 7-chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzothiazole, 6-methylbenzothiazole, 5 bromobenzothiazole, 6-bromobenzothiazole, S-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, S-methoxybenzothiazole, 6-methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4- ethoxybenzothiazole, S-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6- dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6- hydroxybenzothiazole, naphto[2,l-d]thiazole, naphtho[l,2- d]-thiazole, 5-methoxynaphtho[2,3-dlthiazole, S-ethoxynaphtho-[2,3-d]thiazole, 8-methoxynaphtho[2,3-dlthiazole, 7-methoxynaphtho[2,3-d1thiazole, 4-methoxythianaphtheno-7',6',4,5-thiazole, etc.; an oxazole nucleus, e.g., 4-methyloxazole, Smethyloxazole, 4-phenyloxazole, 4,5- diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5- phenyloxazole, benzoxazole, S-chlorobenzoxazole, 5-methylbenzoxazole, S-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5- methoxybenzoxazole, S-ethoxybenzoxazole, 5-chlorobenzoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6- hydroxybenzoxazole, naphtho[2,l-d1oxazole, naphthoI 1,2-d] oxazole, etc.; a selenazole nucleus, e.g., 4-methylselenazole, 4-phenylselenazole, benzoselenazole, 5chlorobenzoselenazole, 5-methoxybenzoselenazole, 5- hydroxybenzoselenazole, tetrahydrobenzoselenazole, naphtho[2,l-dlselenazole, naphtho[l,2-d1selenazole, etc.; a thiazoline nucleus, e.g., thiazoline, 4-methylthiazoline, etc.; a pyridine nucleus, e.g., Z-pyridine, 5-methyl-2-pyridine, 4- pyridine, 3-methyl-4-pyridine, etc.; a quinoline nucleus, e.g., 2-quinoline, 3-methyl-2-quinoline, 5-ethyl-2-quinoline, 6- chloro-2-quinoline, 8-chloro-2-quinoline, 6-methoxy-2-quinoline, S-ethoxy-Z-quinoline, 8-hydroxy-2-quinoline, 4-quinoline, 6-methoxy-4-quinoline, 7-methyl-4-quinoline, 8-chloro- 4-quinoline, l-isoquinoline, 3,4 -dihydro-l-isoquinoline, 3-

isoquinoline, etc.; a 3,3-dialkylindolenine nucleus, e.g., 3,3- dimethylindolenine, 3,3,S-trimethylindolenine, etc.; and, an imidazole nucleus, e.g., imidazole, l-alkylimidazole, l-alkyl-4- phenylimidazole, l-alkyl-4,S-dimethylimidazole, benzimidazole, l-alkylbenzimidazole, l-aryl-5,6-

lalkyl-1H-naphth[ l ,2-dlimidazole, '1 -aryl-3H-naphth[ l ,2-d]imidazole, l-alkyl-S-methoxyl H- naphth-[ l ,2-d]imidazole, etc.; and Q represents atoms necessary to complete a fiveor six-membered nucleus, typically containing a hetero atom selected from nitrogen and sulfur,

such as a 2-pyrazolin-5-one nucleus, e.g., 3-methyl-l-phenyl-2 -pyrazolin- -one, l-phenyl-2-pyi'azolin-5 -one, l-( 2- benzothiazolyl)-3-methyl-2-pyrazolin-5-one, etc.; a 2,4,6- triketohexahydropyrimidine nucleus, e.g., 2-thiobarbituric acid as well as its l-alkyl (e.g., l-methyl, l-ethyl, l-propyl, lheptyl, etc.) or 1,3-dialkyl (e.g., l,3dimethyl, 1,3-diethyl, l,3-dipropyl, 1,3-diisopropyl, 1,3-dicyclohexyl, l,3-di(B- methoxyethyl), etc.; or l,3-diaryl (e.g., l,3-diphenyl, l,3-di- (p-chlorphenyl), l,3di(p-ethoxycarbonylpheny]), etc.); or 1- aryl (e.g., l-phenyl, l-p-chlorophenyl, l-p-ethoxycarbonylphenyl, etc.) or l-alkyl-3-aryl (e.g., l-ethyl-3-phenyl, l-nheptyl-3-phenyl, etc.) derivatives; and a rhodanine nucleus (i.e., 2-thio-2,4-thiazolidinedione series), such as rhodanine, 3-alkylrhodanines, e.g., 3-ethylrhodanine, 3-allylrhodanine, etc., 3-carboxyalkylrhodanines, e.g., 3-(2-carboxyethyl)rhodanine, 3l(4-carboxybutyl)rhodanine, etc. 3-sulfoalkylrhodanines, e.g., 3-(2-sulfoethyl)rhodanine, 3-(3-sulfopropyl)rhodanine, 3-(4-sulfobutyl)rhodanine, etc., or 3- arylrhodanines, e.g., 3-phenylrohodanine, etc., etc.

Included among the complex merocyanine dyes defined by Formula I above are the following typical dye compounds.

TABLE A Dye No. Dye compound II l.3-Diethyl-Sl( I-ethylnaphtho[1,2-d1thiazolin-2- ylidene )ethylidene ]-2-[ 3-ethyl-4-oxo-2thiooxo- S-thiazolidinylidene )ethylidene I-A-imidazolidinone III 3 Ethyl-2-[ l -ethyll1exahydro-4 ,6-dio xo-2 th ioxo- 5- pyrimidinylidene )ethylidene] l -phenyl-5-(( 1,3,3- trirnethyl-2-indolinylidene )ethylidene ]-4- imidazolidinone l,3 Diethyl-5-l 3-eIhyl-2-benzothiazolinylidene ethylidene1-2-fl3-methyl-5-oxo-I phenyl-Z- pyrazolin-kylidene )ethylidenel-4-irnidazolidinone V 3-Ethyl-5-[( l-ethyl-Zl lI-l)-B- naphthosele nazolylidene)-isopropylidene ]-2( 3- ethyl-4 0xo-2-thiono-5thiazniylidene )-4- lhiazolidone VI 3-EthylS-[(3-ethyl-2- benzoxazolinylidene )ethylidene I-Z-l 3-ethyl-4- oxo-Z-thioxo-S-thiazolidinylidene )-elhylidene ]-4- thiazolidinone VII 3-Ethyl-5-[( l-ethylnaphlho[ l,2-d]thiazolin-2- ylidene )ethylidene ]-2-[ 3-ethyl4-oxn-2-thioxo-5- thiazolidinylidene )ethylidene ]em- I -phenyl-4- imidazolidinone The complex merocyanine dyes represented by above Dye No. V have previously been described in the prior art in references such as Fry et al. US. Pat. No. 2,388,913, issued Nov. I3, 1945; Brooker, US. Pat. No. 2,454,629, issued Nov. 23, I948; Aubert et al., U.S. Pat. No. 2,656,351, issued Oct. 20, 1953; etc. Dyes represented by Dye Nos. 1, II, III, IV, VI and VII can be conveniently prepared by the general process described in copending application Jenkins, Ser. No. 657,082, filed July 3 l 1967, entitled Synthesis of Trinuclear Dyes. Thus, the above-mentioned dyes are prepared by condensing a compound of the formula:

with a compound of the formula:

III. m

f C-CH CH-e, teams I ,3-Diethyl-5-[( l-ethylnaphtho[ l,2-d]thiazolin-2- ylidene)ethylidene]-Z-methyl-4-oxo-2-imidazolinium iodide (1 mol., 1.30 g.), 5-acetanilidomethylene-B-ethylrhodanine (1 mol., 0.80 g.), acetic anhydride (200 percent excess, 0.50 g.) and triethylamine l mol.+200 percent, 0.75 g.) was dissolved in pyridine (10 ml.) and the solution was heated under reflux for twenty minutes. The hot reaction mixture was transferred to a beaker containing acetic anhydride (2.0 (mL). The warm solution was treated first with N,N-diethylethylenediamine (2.0 ml.) and then diluted with methanol ml.) The solution was chilled overnight and the crude dye was collected by filtration, washed with methanol and dried. The crude dye was recrystallized by dissolving in hot pyridine containing acetic anhydride. The resulting solution was first treated with N,N- diethylethylenediamine and then diluted with methanol. The solution was chilled and the dye was collected by filtration, washed with methanol and dried. After a final recrystallization from pyridine and methanol, the yield of pure dye was 0.45 g. (32 percent), m.p. 253.0255.0 C. (Ice.

The sulfonated organic supersensitizers useful in practicing my invention comprise polynuclear aromatic compounds containing at least one sulfo group. The term polynuclear aromatic as used herein is intended to mean two or more benzene rings fused together (for example, as in naphthalene, pyrene, etc.) or at least two benzene rings of aromatic rings directly joined together (for example, as in diphenyl, terphenyl, quaterphenyl, etc.) or through an aliphatic linkage. Such sulfonated derivatives can conveniently be represented by the following general formula:

IV. D-SO M wherein D represents a polynuclear aromatic group as defined above and M represents a hydrogen atom or a water-soluble cation salt group (e.g., sodium potassium, ammonium, triethylammonium, triethanolammonium, pyradinium, etc.). Among the most useful of the sulfonated derivatives embraced by Formula IV above are the compounds represented by the following general formula:

CH=C H-B:

wherein B represents a 1,3,5-triazin-6-ylamino group, B The products of Formula Va have been previously emrepresents an aromatic group (i.e., benzene or substituted ployed in the textile field, and are sold under such tradenames benzene) M h he values given above. as Leucophor B, Calcofluor White MR, Tinopal (SP, WR,

Typical of the sulfonated derivatives of Formula V above, BV277, 28, GS, NG), Blancofor SC, Hiltamine (BSP, N, 801., wherein B represents a 1,3,5-triazin-6-ylamino group (i.e., a 5 6T6), and the like.

1,3,5-triazin-2-ylamino group) are the compounds selected The dibenzothiophenedioxide compounds of Formula VI from those represented by the following general formula: have, in general, been previously described in the prior art. Va See, for example, U.S. Pat. Nos. 2,573,652; 2,580,234; and

2,563,493. Further examples of the preparation of such com- R4 10 pounds are given in J. E. Jones, J. Spence, and J. A. Van Alll l I lan, U.S. Pat. No. 2,937,089, issued May 17, 1960. Other ex- N N CH:CH am les of sulfonated derivatives embraced by Formula IV RT 1 above which can advantageously be used 1n my inventlon can S 03M 303M 1 R5 be prepared according to the methods described in application Ser. No. 575,160. Still other examples of compounds wh M has the Values given above and 4, R5: 6. 1 each represented by Formula IV above which can be used in my inrepresents a hydrogen atom or a substituent group, such as vention have been previously described in B. H. Carroll, J. E. hy r y y y a. p xy y pp y Jones, and J. Spence, U.S. Pat. 2,950,196, issued Aug. 23, etc.), alkoxyl(e,g., methoxyl, ethoxyl, etc.), a halogen atom 1960. (See, in particular, the compounds of Formulas II, III (e.g., chlorine, bromine, etc.), a heterocyclic radical (e.g., dlv f hat t t). m p l ny p p y an alkylthio g p -g-, Compounds selected from those of Formula v above methy t o, ethy 1 an arylthio g p .g., phenwherein B represents a 2-benzotriazolyl group can be yl hi tolylt w), a heterocyclythio g p prepared according to methods previously described in the benzothiazylthio, etc.) an amino group, an alkylamino group prior art. See, for example, U.S. Pat. to Zweidler et al. No.

( g-. y min yl m .p pyl m m yl ino, 2,713,057, dated July 12, 1955; Keller et al., U.S. Pat. No. di hy in y min y xy min B-hydrox- 2,684,966, dated July 27, 1954; Zweidler et al., U.S. Pat No. yethylamino, di-B-hydroxyethylamino, B-sulfoethylamino, 2,784,197, dated Mar. 5, 1957', and Keller et al., U.S. Pat No.

an y min g p -g-a n mn P- 2,784,183, dated Mar. 5, 1957. A somewhat related group of anisylamino, o-, mand p-chloroanilino, 0-, mand p-toludino, compounds containing a 2-benzotriazoly1 group which can be 0-, m-, and p-carboxyanilino, hydroxylanilino, sulused in my invention have been previously described in U.S. fonaphthylamino, o-, mand p-aminoanilino, p- Pat. No. 2,733,165. Such compounds are embraced by Foracetamidoanilino, etc.), etc. mula IV above.

Compounds of Formula Va wherein R R R and/or R Typical sulfonated derivatives embraced by Formulas IV, each represents a heterocyclylamino group (e.g.,2- V, Va and VI above are (chemical formulas are given for varibenzothiazoleamino,Z-pyridylamino, etc.) can also be used in ous types to aid in identification): 1. a sulfonated triazolostilpracticing my invention. bene, e.g., of the type shown in U.S. Pat. No. 2,713,057.

Another group of sulfonated derivatives which are useful in 4,4'-di(4", 6"-dihydroxy-2"-s-triazinylamino)stilbene-2,2'- practicing my invention are those represented by the following disulfonic acid 3. 4,4-bis[4(3 '-sulfoanilino)-6-amino-sgeneral formula: triazin-Z-ylamino]-stilbene O O 4. Tinopal-WR, a sulfonated triazinyl stilbene y 5. Tinopal-ZB, a sulfonated triazinyl stilbene R 6. A sulfonated triazinyl stilbene, e. g., of the type shown in U.S. Pat. No. 2,595,030, or British Pat. No. 595,065 Bl Rm 7. 4,4'-bis[2-(4-sulfoanilino-Z-B-hydroxyethylamino)-1,3,5

triazin-6-ylamino]sti1bene-2,2-disulfonic acid wherein R8 is an acylamido group (egq acetamido, 8. 4,4 -b1s(2,4-d1hydroxy-l,3,5-tr1az1n-6-ylam1no)d1benzyl- 2,2-disu1fonic acid fobenzanlldo' 4-.methoxy'3'sulfobisnzamldo g'ethox- 9. 4,4'-bis(Z-B-hydroxyethylamino-4-ani1ino-l,3,5-triazin-6 ybenzamdq benzamld lamino)-14-dist r 1benzene-2 2-disulfonic acid methyl-2-methoxybenzamido, l-naphthoylamino, 2- y y y 10. 5-methoxy-2-(4-styryl-3-sulfo)phenyl-l,2,3-benzotriazole sodium salt 1 l. Calcofluor White-MR, a sulfonated triazinyl stilbene naphthoylamino, 2,4-dimethoxybenzamido, 2-pheny1- benzamido, Z-thienylbenzamido) or a sulfo group, R represents an acylamido group (e.g., as defined by R, above), or a sulfoaryl group (e.g., sulfophenyl, p-sulfodiphenyl, etc.) and R represents a hydrogen atom or a sulfo group, said compound containing at least one sulfo group. (12) .,a, "M2,. Nd

Compounds of Formula Va which can advantageously be 0 o employed 1n practicing my invention have been described in s i:

one or more of the following representative patents: U.S.: Q NH- 2.171.427 Aug. 29. 1939 2.473.475 June 14. 1949 Hols 803E 2.595.030 Apr. 29. 1952 2,660,578 Nov. 24. 1953 2,945.762 July 19. 1960 British: 3 ,7-bis( 2-phenylbenzamido 2 ,8-disu1fodibenzothiophene- 595,065 Nov. 26. 1947 q 623349 My 1949 13. 3,7-b1s( 2-th1enylam1do)-2,8disulfodibenzothlophene diox- 624,051 May 26. 1949 ide sodium salt 624.052 May 26, 1949 678.29 Sept 3 I952 14. 3 [4 (4 methoxy 3 sulfobenzam1do)pheny1] 7 (4 68154; 0cL 1952 methoxy-3-sulfobenzamido)dibenzothiophene dioxide sodium 705.406 Mar. 10. 1954 salt l5. chrysens--sulfonic acid sodium salt 16. pyrene-3-sulfonic acid sodium salt 17. Phenanthrene-3-sulfonic acid sodium salt 18. 2,3-dimethylnaphthalene-l-sulfonic acid sodium salt 1 9. 4-[-phenoxy-6-( B-hydroxyethylamino )-s-triazin-2- ylamino -4 '-[4-chloro-6-di( B-hydroxyethyl )amino-s-triazin- 2-ylamino1-stilbene-2 ,2'-disulfonic acid 20. 2,8-bis[4-(4-sulfoanilino)-o-hydroxy-s-triazin-Z-ylamino]- carbazole 21. 4,4 '-bis( 4 ,6-di( B-hydroxyethylamino )-s-triazin-2- yl)benzi-dine-2,2'-disulfonic acid 22. 2-laurylamino-4,6-di(4-sulfoanilino)-s-triazine 23. 4,4'-bis {4-[4'-(N', 4"-sulfobenzyl-N- ethyl )aminoanilino 1 -6-hydroxy-s-triazin-2-ylamino] stilbene- 2,2-disulfonic acid 24. -acetamido-2-(4-styryl-3-sulfo)phenyl-1,2,3- benzotriazole sodium salt 25. 2,7-diacetamido-3,6-disulfodibenzothiophene-S,S-dioxide sodium salt 26. 4-sulfo-o-terphenyl sodium salt (Lour. Organ. Chem., Vol. 14 (1949), pg. 163

27. pyrene-3-(4-methoxy-3-sulfostyryl)ketone sodium salt 28. 3,7-bis(4-methyl-2-methoxybenzamido)-2,8-disulfodibenzothiophene-S,S-dioxide sodium salt As can be seen above, many of the sulfonated derivatives are employed in the form of their water-soluble salts, such as alkali metal (e.g., sodium, potassium, etc.) salts, or ammoniurn or amine (e.g., triethylamine, triethanolamine, pyridine, aniline, etc.) salts. By thus using these derivatives, they can be added to the emulsions in substantially neutral aqueous solutions without disturbing the pH of the emulsions.

In accordance with the practice of this invention, any reducing agent (i.e., a material capable of reducing silver halide) can be employed which coacts with the complex merocyanine dye and sulfonated polynuclear organic compound to further enhance the blue sensitivity of the silver halide emulsion. Particularly good results are employed with dihydroxy substituted reducing agents. Typical dihydroxy compounds which can be employed in the practice of this invention are selected from the group consisting of the benzenes, gamma-lactones, pyronimides, tetronimides, furans and pyrroles, which contain at least two hydroxyl groups.

Typical useful dihydroxy substituted compounds which can be utilized include hydroquinone, resorcinol, pyrocatechol, 3- methylpyrocatechol, toluhydroquinone, naphthalenediols, etc.; 'y-lactones such as ascorbic acid, isoascorbic acid, etc.; 3- hydroxy tetronimides; 3,4,5-trihydroxy-5,b-dihydro-pyronimides; and amino hexose reductones wherein the moiety comprising the subject reductones can be represented by the following formula wherein: R and R can be an alkyl radical, preferably having one to eight carbon atoms or together the necessary atoms to make a heterocyclic radical with the nitrogen atom, preferably having a five to six atom nucleus and including a second nitrogen atom or an oxygen atom such as morpholino, piperazino, pyrrolino, pyridino, pyrimidino, piperidino and the like.

The typical suitable tetronimides, pyronimides and amino hexose reductones are set out in Table B:

Table B 5-Phenyl-3-hydroxy tetronimide 5-( 4-Carboxyphenyl )-3-hydroxy tetronimide,

5-(3,4Dimethoxyphenyl )-3-hydroxy tetronimide,

5-( n-Butyl )-3-hydr0xy tetronimide 5-( 2-Furyl )3-hydroxy tetronimide (5-a-Furyl-3 ,4-dihydroxy-2-imino-2 ,S-dihydrofuran and the like;

5 ,6-Diphenyl-3 ,4,5 -trihydroxy-5 ,6-dih ydro-pyronimide 5 ,6-Di-n-butyl-3 ,4,5-trihydroxy-5 ,-dihydro-pyronimide,

5 ,6-Di-morpholino-3 ,4,5 -trihydroxy-5 ,6-dihydro-pyronimide, 5 ,6-( Z-Sulfophen yl )-3 ,4,5-trihydroxy-5,-dihydro-pyronimide,

and the like;

Dimethylamino hexose reductone Di-n-hexylamino Di-n-butylamino hexose reductone Di-n-hexylarnino hexose reductone Morpholino hexose reduction Piperazino hexose reductone Pyrrolino hexose reductone Piperidino hexose reductone and the like.

The tetronimides and pyronimides such as mentioned above may be prepared by the methods described in British Pat. No. 782,304, Swiss Pat. No. 322,985, and in Helv. Chim.Acta, 39, 1,780 (1956). The above, and still other 3-hydroxy tetronimides and 3,4,5-trihydroxy-5,o-dihydro-pyronimides that are suitable, are disclosed in Salminen, U.S. Pat. No. 3,330,655, issued July 1 l, 1967.

The amino hexose reductones of the invention are derived from sugars, especially D-glucose, although other six carbon or hexose reducing sugars such as D-galactose, D-mannose, D- fructose, L-sorbose or the like can be used. A typical method for preparing the subject reductones comprises heating in a reaction medium substantially free of water a hexose reducing sugar and an aliphatic or cyclic secondary amine in the presence of an acidic reductone-forming catalytic agent such as phosphoric acid, boric acid, acetic acid, succinic acid or the like. The removal of three molecules of water results during the formation of the subject amino hexose reductones. The mentioned reductones and other related suitable reductones and methods for preparing such are described in Hodges, U.S. Pat. No. 2,936,308.

According to the invention, one or more of the sulfonated organic compounds, one or more of the reducing agents and one or more of the complex merocyanine dyes of the invention are added singly or in combination to light-sensitive photographic silver halide emulsions to supersensitive the emulsions.

The invention is particularly directed to gelatinosilver-halide developing-out emulsions. However, the supersensitizing combinations can also be employed in silver halide emulsions in which the carrier or vehicle is a hydrophilic colloid other than gelatin, such as albumin, agar-agar, gum arabic, alginic acid, etc., or a hydrophilic resin such as polyvinyl alcohol, polyvinyl pyrrolidone, a cellulose ether, a partially hydrolyzed cellulose acetate, acrylamide polymers, etc., which has no deleterious effect upon the light-sensitive silver halide. The sulfonated organic compounds, and reducing agents and the dyes of Formula 1 above can be employed in the combination of the invention in various concentrations depending upon the particular emulsion, concentration of the silver halide, particular results desired, etc. The optimum concentration of an individual sensitizing dye can be determined in a manner well known to those skilled in the art by measuring the sensitivity of a series of test portions of the same emulsion, each portion containing a different concentration of the sensitizing dye. In general, the sulfonated organic compounds and reducing agents in my invention have little or no sensitizing action by themselves alone in the emulsions employed. Ordinarily, the optimum or near optimum concentration of the complex merocyanine dyes herein is ofthe order of from 0.01 to 0.30 g. per mole of silver halide in the emulsion, and that of the sulfonated organic compound and reducing agents herein are of the order of from 0.50 to 4.0 g. and 1.0 to 8.0 g., respectively.

The methods of incorporating sensitizing dyes in silver halide emulsions are well known to those skilled in the art and these known techniques are employed in dispersing the dyes of the invention in the emulsions. ln practicing my invention and the sensitizing dyes, the sulfonated organic compounds and the reducing agents can be directly dispersed in the emulsions, or they can first be dissolved in some convenient solvent, such as pyridine. methyl alcohol, acetone, etc. (or mixtures of such solvents), or diluted with water in some instances, and added to the emulsions in the form of these solutions. If desired, the components can be separately dissolved in a given solvent and added separately to the emulsion, or they can be dissolved in the same or different solvent and these solutions mixed together before addition is made to the silver halide emulsions. The dyes, sulfonated organic compounds and reducing agents of the invention are dispersed in the finished emulsions in such a manner as to be uniformly distributed throughout the emulsions prior to coating on a suitable support, such as paper, glass, cellulose ester film, polyvinyl resin film (e.g., polystyrene film, polyvinyl chloride film, etc.) polyester film, etc. The following procedure has been found quite satisfactory: Stock solutions of the sulfonated organic compounds, reducing agents and the dyes of Formula l above are prepared by separately dissolving these components inappropriate solvents as described above. Then, to the flowable silver halide emulsion, the desired amount of stock solution of one of the dyes is slowly added while stirring the emulsion. Stirring is continued until the dye is thoroughly incorporated in the emulsion. Then, the desired amount of stock solution of one of the sulfonated organic compounds is slowly added to the emulsion while stirring. Next, the desired amount of one of the reducing agents is added. Stirring is continued until the added materials are thoroughly incorporated in the emulsion. The supersensitized emulsions can then be coated on a suitable support and the coating allowed to dry. In some instances, it may be desirable to heat the supersensitized emulsion for a few minutes before coating onto the suitable support. The details of such coating techniques are well known to those skilled in the art. The foregoing procedure and proportions are to be regarded only as illustrative. Clearly, the invention is directed to any silver halide emulsion containing a supersensitizing combination of the invention, e.g., gelatino-silver chloride, -chlorobromide, -chloroiodide, -chlorobromoiodide, -bromoiodide, etc., emulsions.

Fine grain emulsions can also be employed herein. These may be prepared by precipitating photosensitive silver halide crystals, in an aqueous medium, in the presence of an acid substituted aryl mercaptan, e.g., thiosalicylic acid, dissolved in said medium. Gelatin or other suitable hydrophilic colloid is added and the emulsion obtained is chilled and set. The chilled emulsion is then shredded into small noodles and washed in running tap water. After washing, the emulsion is remelted, and the volumne, pH and Pag are adjusted. A fine grain gelatino-silver bromoiodide emulsion prepared in the above manner and containing a dye combination of the invention is particularly useful for recording radiations in the region of the spectrum ranging about from 300 to 750 nm. in fine detail. Further details for preparing such fine-grain emulsions can be had by reference to copending application of Sutherns, Ser. No. 622,034, filed March 10, 1967.

The emulsions of this invention can contain the chemical sensitizers, speed increasing compounds, plasticizers, hardeners and coating aids, and the silver halide may be dispersed in any of the binders, that are described and referred to in Graham et al. US Pat. No. 3,046,129, issued July 24, 1962.

The following examples are included for further understanding of the invention.

EXAMPLES 1 to 7 These examples illustrate the supersensitization produced by various supersensitizing combinations of the invention containing a complex merocyanine dye defined by Formula 1 above in the region of the spectrum of wavelengths above about 510 nm. The testing procedure and the results are set forth in the following description and Table 1. The specified complex merocyanine dyes are identifiable by reference to above Table A, while the specific sulfonated organic compounds and reducing agents are named in the footnotes to the following table of these examples.

To different portions of the same batch of melted gelatinosilver bromoiodide emulsion, containing 0.77 mole percent iodide, of the type described by Trivelli and Smith, Phot. Journal, 79, 330 (1939), are added the individual complex merocyanine dyes, sulfonated organic compounds and reducing agents in the proportions given in Table l hereinafter. in each case, after being digested at about 40 C. for 5 minutes, the emulsion is coated at a coverage of 432 mg. silver per square foot on a cellulose acetate film support. A sample of each coating is exposed on an Eastman 1B Sensitometer to light from a tungsten source modulated by a step-wedge and Kodak Wratten No. 16 filter and processed for 3 minutes at 20 C. in Kodak developer D19 which has the following composition:

N-methyl-p-aminophenol sulfate 2.0 g. Hydroquinone 8.0 g. Sodium sulfite (desiccated) 90.0 g. Sodium carbonate (monohydrate) 52.5 g. Potassium bromide 5.0 g. Water to make l.0 g.

and then fixed in a conventional sodium thiosulfate fixing bath, washed and dried. Densitometric measurements are then made of the developed images of each coating. The relative speed values are determined by the exposure necessary to produce a density of 0.3 above fog, an arbitrary relative speed of 100, or more as indicated, being chosen for the control containing no dye. The results are listed in the following table together with the values for gamma and fog.

TABLE 1 Snpvi'svusltizntion of complex inurm-ymtiiw ilyus Relative minus llllll DyuNiLmid Atltltlldllm uutl spvurl (#1 cont, (g7 conc.1g./rnole wruttenl Ex. N0 niole silver) silver llltur 7 Fog 151 1.40 .01) Hi0 l 15 .08 331 1 32 .00 417 1 27 .00

Addendum.

X=Calvofiuor White MR is a sulionated triazinyl stilbene 0.52.. a bis(striazin-Z-ylamino)stilbeue-Zfl'disulionie acid (sodium salt).

A= Ascorbic acid.

B Piperadino hexose reductone.

C d-Isoascorbic acid.

D Hydropuinone.

E =5,6-di-phenyl-3,4,5-trihydroxy-5,6dihydro pyronimide.

EXAMPLES 8-12 These examples illustrate that the inclusion of a reducing agent of the invention into the supersensitizing combinations herein decreases the desensitization of the complex merocyanine dyes of the invention. The testing procedure is exactly the same as that described for above Examples 1 to 7 except that the exposures of the samples are made through Wratten Filter No. 35 Wratten Filter No. 38A Chance Glass Filter (which combination transmits only light in the blue region of the spectrum). thereby giving relative blue speeds for each of the examples. The results of these tests are set forth in the following Table 2.

TABLE 2 Decrease in desensitization of complex merocyanino dyes by addition of reducing agent Relative blue speed #35+#38A Dye N o. Addendum Wratten and cone. and cone. filters plus (gJmole (gJmole Chance Ex. N0. silver) silver) glass fil. 'Y Fee .03 19 1.36 05 .03 40 1.50 O8 .03 X 0.75 18 1.02 .05 .03 A+X 1.5+. 75 53 1.46 .00

.03 None 115 1. 63 .04 .03 1.5 151 1.4.1 .06 03 X 0. 75 123 1. 53 04 .03 A+X. 1.5+.75 138 1.35 .05

.03 None 78 1.35 .04 .03 B 1.5 87 1.43 .05 .03 X 0.75 7 1. .05 .03 B-i-X..- 1.5+.,75 B3 1.25 .06

. 58 1. 46 .06 54 1. 34 .03 54 1. 44 .08 05 1. 48 .05 95 1. 52 .07 105 1.45 .06 87 1.50 06 05 1.40 .04 i 76 1.54 05 76 1.56 04 09 1. 52 .06 73 1. 46 .04 .03 1. 55 1.40 .09 .03 F+X 1.5+.75 73 1.44 .04

Addendum:

X CalcOfiuor White M R1 A=Aseorbic acid. B Piperadino hexose reductone. C d-Isoascorbic acid. D Hydroquinone. E 5.6-di-phenyl-3.4,5trihydrox y-5.6-dihydro pyronimide. F 5-a-furyl-3,4-dihydroxy-2-imino-2,5-di-h yd roiuran.

It will be noted from above Table 2 that the addition of the specified reducing agents produce a substantial improvement in the relative blue speed in each of the examples which contain just dye and sulfonated organic compound.

EXAMPLES 1 3-15 TABLE 3 A. Decrease in sensitization ratio of dicarboeyaniue dyes with addition of reducing agent to dye and Calcofiuor White MR (dye Nos. 111 and 1X) Relative blue speed (#35+#38A W ratten filter plus Chance glass ill.)

D ye N o. and cone. (gJmole silver) Addendum and cone. (I I.!m0le silver) B. Effect on desensitization of dicarbocyanine dyes by addition of reducing agent a -0- co ent:

None A 1.5

Addendum: A and X are as defined in above Examples 1 to 8; Dye N0. VIII: 3,3-diethyl thiadiearhoeyanine iodide; Dye No. IX: 3,3-diethyl selenadicarbocyanine iodide.

EXAMPLES 16-17 These examples indicate that simple merocyanine dyes are not supersensitized by either the reducing agent, by Calcofluor White MR or by the combination of these two compounds (A of Table 4), and show only slight decrease in desensitization (B of Table 4). The simple merocyanine dye in these examples is identifiable from the footnote to the Table. The testing procedure is exactly the same as described in the foregoing examples for both A and B sections of the Table, except that the exposures for A are made through Wratten Filters No. 35 No. 38A Chance Glass Filter (for relative minus blue speed. etc.). The test values appear in the following Table 4.

TABLE 4 A. Decrease in sensitization ratio of a simple merocyaniue dye with addition of reducing agent to the dye with Calcofiuor White MR (dye No. X)

Dye No. and cone. (g.,/molesilver) Addendum and cone. (g. mole silver) Fog None Ann." 4.0 .08 X 2.0 A+X 4+2 B. Etfeet on desensitization of a simple merocyanine dye by addition of a reducing agent (dye No. X)

. *8! l. 05 4. 0 "105 ll. 70 .12 1.0 '95 1.40 .05

Referring to above Table 4, it will be seen that simple merocyanine dyes also do not produce the advantageous supersensitizing results of the complex merocyanine combinations of this invention.

it will be understood that any other complex merocyanine dye defined by Formula I above can be substituted in the preceding examples of the invention to give generally similar advantageous supersensitizing results for light-sensitive photographic silver halide emulsions. Also, the sulfonated organic compounds and reducing agents in the supersensitizing combinations of the examples can be substituted with any other of those previously mentioned as being suitable with similar advantageous supersensitizing results for such emulsions.

Although the invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the in vention.

Iclaim:

l. A photographic silver halide emulsion sensitized with a combination comprising l) a complex merocyanine dye having three fiveto six-membered nitrogen containing heterocyclic nuclei joined at a carbon atom thereof by a linkage selected from the group consisting of a double bond and a methine linkage, one terminal nucleus of said dye being a basic heterocyclic nucleus of the type used in cyanine dyes, and the other two nuclei of said dye being acidic ketomethylene heterocyclic nuclei of the type used in merocyanine dyes, said dye having the amidic chromophoric system; (2) a sulfonated polynuclear aromatic organic supersensitizer; and, (3) sufficient amount ofa sliver halide reducing agent to effectively increase the blue speed of the emulsion.

2. A photographic silver halide emulsion spectrally sensitized with (l) a complex merocyanine dye represented by the following formula:

wherein n represents a positive integer of from 1 to 2; m and p each represents a positive integer of from 1 to 3; L represents a methine linkage; R represents a member selected from the group consisting of an alkyl group and an aryl group; A represents a member selected from the group consisting of an atom of sulfur and the group N-R R and R each represents a member selected from the group consisting of an alkyl group containing from one to four carbon atoms and an aryl group; 2 represents the nonmetallic atoms necessary to complete a heterocyclic nucleus of the type used in cyanine dyes containing from five to six atoms in the heterocyclic ring; and Q represents the nonmetallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting ofa 2-pyrazolin-5-one nucleus; a 2-thiobarbituric acid nucleus; and, a rhodanine nucleus; (2) a water-soluble sulfonated organic compound represented by the following formula:

S OaM wherein B represents a 1,3,5-trazin-6-ylamino group, B represents an aromatic group, and M represents a member selected from the group consisting of a hydrogen atom and an alkali metal atom; and (3) a dihydroxy substituted reducing agent selected from the group consisting of the benzenes, gamma lactones, tetronimides, pyronimides, furans and pyrroles which contain at least two hydroxyl groups.

3. A photographic silver halide emulsion sensitized with a supersensitizing combination comprising (i a complex merocyanine dye represented by the following formula:

wherein n represents a positive integer of from i to 2; m and p each represents a positive integer of from i to 3; L represents a methine linkage; R represents a member selected from the group consisting of an alkyl group and an aryl group; A represents a member selected from the group consisting of an atom of sulfur and the group N-R R and R each represents a member selected from the group consisting of an alkyl group containing from one to four carbon atoms and an aryl group; Z represents the nonmetallic atoms necessary to complete a heterocyclic nucleus of the type used in cyanine dyes containing from five to six atoms in the heterocyclic ring; and Q represents the nonmetallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of a 2-pyrazolin-5-one nucleus; a 2-thio-barbituric acid nucleus; and a rhodanine nucleus; (2) a water-soluble sulfonated organic compound represented by the following formula:

wherein B represents a l,3,5-triazin-6-ylamino group, B represents an aromatic group, and M represents a member selected from the group consisting of a hydrogen atom and an alkali metal atom; and (3 an organic reducing agent containing at least two hydroxyl group substituents selected from the class consisting of a dihydroxyarylene; a )t-lactone; a 3- hydroxy tetronamide; a 3,4,5-trihydroxy-5,o-dihydropyronimide; and, an amino hexose reductone wherein the amino moiety of said reductone has the formula:

l a li -N- wherein R and R are selected from the group consisting of alkyl radicals and together with the nitrogen atom the necessary atoms to form a nitrogen-containing heterocyclic radical.

4. A photographic silver halide emulsion spectrally sensitized with a complex merocyanine dye selected from the group consisting of: l-ethyl-4-[(3-ethyl-2-benzothiazolinylidene)-ethylidene]-2-[(3-ethyl-4-oxo-2-thioxo-5- thiazolidinylidene)-ethylidene1-3-phenyl-5-imidazolidinone; l,3-diethyl-5-[( l-ethylnaphtho[ l,2-d]thiazolin-2- ylidene)ethylidene]-2-[(3-ethyl-4-oxo-2-thioxo-5-thioxo-5- thiazolidinylidene)ethylidene]gO-4-imidazolidinone; 3-ethyl-2-[ l-ethylhexahydro-4,6-dioxo-2-thioxo-5-pyrimidinylidene)- ethylidene]- l -phenyl-5-[( l,3,3-trimethyl-2-indolinylidene)ethylidene]-4-imidazolidinone; l,3-diethyl-5-[(3- ethyl-Z-benzothiazolinylidene )ethylidene -2-[ 3-methyl-5 oxo-l -phenyl-2-pyrazolin-4-ylidene)ethylidene ]-4 imidazolidinone; 3-ethyl-5-[( l-ethyl-2(1H)-B- naphthoselenazolylidene )isopropylidene]-2-( 3-ethyl-4-oxo-2- thiono-S-thiazolylidene)-4-thiazolidone; 3-ethyl-5-[(3-ethyl- 2-benzoxazolinylidene )ethylidene]-2-[ 3-ethyl-4-oxo-2-thiox- 15 o--thiazolidinylidene)ethylidenel-4-thiazolidinone; 3-cthyl- 5 l-ethylnaphthol l ,2-d]thiazolin-2-zylidene)ethylidene1-2- [(3-ethyl4-oXo-2-thioxo-5-thiazolidinylidene)ethylidene1- lphcnyl-4-imidazolidinone; said emulsion being supersensitized with a sulfonated triazinylstilbene and a reducing agent selected from the group consisting of a dihydroxy substituted benzene; ascorbic acid; isoascorbic acid; 5-a-furyl-3,4- dihydroxy-2-imino-2,S-dihydrofuran; 5 .6-diphenyl-3 ,4,5- trihydroxy-S,dihydro-pyronimidc; and piperidino hexose reductone.

5. A photographic silver halide emulsion supersensitized with the combination of 1-ethyl-4-[ 3-ethyl-2- benzothiazolinylidene )-ethylidene ]-2-[ 3-ethyl-4-oxo-2- thiooxo-S-thiazolidinylidene)-ethylidene]-3-phenyl-5- imidazolidinone; ascorbic acid; and a bis(s-triazin-2- ylamino )stilbene-2,2'-disulfonic acid, sodium salt.

6. A photographic silver halide emulsion supersensitized with the combination of l,3-diethyl-5-[( l-ethylnaphtho-l 1,2- d ]thiazolin-2-ylidene)ethylidene]-2-[( 3-ethyl-4-oxo-2-thiooxo-5-thiazolidinylidene)ethylidene]-4-imidazolidinone; ascorbic acid; and, a bis(s-triazin-2-ylamino)stilbene-2,2'-disulfonic acid, sodium salt.

P0-1050 UNITED STATES PATENT OFFICE 5 69 CERTIFICATE OF CORRECTIQN Patent No. 3,649,289 Dated March l t, 1972 Inventor(s) y L- Hiller It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

T Column 1, line 56, "a" should read ---the---. 1

Column 2, line 35, that part of formula reading naphto should read ---naphtho--- Column 2, line LO, Smethyloxazole" should read 5-methyloxazole Column 2, line 51, "5chlorobenzoselenazole should read 5ehlorobenzoselenazole Column 3, line 16, that part of formula reading "3l( 4" should read E-( L- Column 3, line 19, 3- ohenylrohodanine should read 3- phenylrhodanine Column 3, line 38, that part of formula reading "ethyliden e 7l" should read ethylidene7-l Column 3, line 56, that part of formula reading ethylidene7em-l' should read ethyliden e 7-l Column L, line 37, "(2.0(ml.)" should read --(2.0 ml.).

Column 4, line 63, pyradinium" should read --pyridinium--.

Column 7, line 5 that part of formula reading L-FphenoXy" should read -[5-phenoxy Column 8, line 23, "Di-n-hexylamino" should be deleted.

Column 8, lines 2M-25, Di-n-hexylamino heXose reductone" should be on a separate line and not a continuation of the line in L which it has been printed.

Page 2 5 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,6LLq 28o Dated March 1%, 1972 Inventor(s) y Hiller It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, line 26, "reduction" should read --reductone--.

Column 8, line 55, "supersensitive" should read ---supersensitize- Column 8, line 61, before "albumin" for example, should be inserted.

Column 9, line 12, before "the sensitizing" and" should be deleted.

Column 9, lines 3233, "inappropriate" should read --in appropriate---,

Column 10, line 34, "1.0 g," should read -l,O liter--- Column ll, line 8, that part of formula reading 2,2' disulfonic should read ---2,2'-disulfonic-.

Column ll, line 12, "Hydropuinone should read ---Hydroquinone--.

Column 12, line 12, "along" should read ---alone---.

Column 12, line H3, "A-l-X" should read ---X--.

Column 13, line 8, "n+5" should read ++2---.

Column 13, line 48, 'sliver should read ---silver-.

Column l l, line 68, that part of formula reading "thioxo-5- thioxo-5-" should read ---thioXo-5- Column 1 L, line 69, that part of formula reading "gO L" L should read L J Page 3 $32 23 I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN Patent No. 3,649,289 Dated March 1M, 1972 Inventor(s) a y L. Hiller It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 15, line 9, that part of formula reading "5,6dihydro" should read ---5,6-dihydro Column 16, line H, that part of formula reading "gO-l" should read -1 Column 16, line 13, "slat" should read ---salt-.

Column 16, line 17, that part of formula reading "gO-l' should read -1 Column 16, line 20, slat should read ---salt-.

Signed and sealed this 12th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

2. A photographic silver halide emulsion spectrally sensitized with (1) a complex merocyanine dye represented by the following formula: WHEREIN n represents a positive integer of from 1 to 2; m and p each represents a positive integer of from 1 to 3; L represents a methine linkage; R1 represents a member selected from the group consisting of an alkyl group and an aryl group; A represents a member selected from the group consisting of an atom of sulfur and the group =N-R3; R2 and R3 each represents a member selected from the group consisting of an alkyl group containing from one to four carbon atoms and an aryl group; Z represents the nonmetallic atoms necessary to complete a heterocyclic nucleus of the type used in cyanine dyes containing from five to six atoms in the heterocyclic ring; and Q represents the nonmetallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of a 2-pyrazolin-5-one nucleus; a 2-thiobarbituric acid nucleus; and, a rhodanine nucleus; (2) a water-soluble sulfonated organic compound represented by the following formula: wherein B1 represents a 1,3,5-trazin-6-ylamino group, B2 represents an aromatic group, and M represents a member selected from the group consisting of a hydrogen atom and an alkali metal atom; and; (3) a dihydroxy substituted reducing agent selected from the group consisting of the benzenes, gamma lactones, tetronimides, pyronimides, furans and pyrroles which contain at least two hydroxyl groups.
 3. A photographic silver halide emulsion sensitized with a supersensitizing combination comprising (1) a complex merocyanine dye represented by the following formula: wherein n represents a positive integer of from 1 to 2; m and p each represents a positive integer of from 1 to 3; L represents a methine linkage; R1 represents a member selected from the group consisting of an alkyl group and an aryl group; A represents a member selected from the group consisting of an atom of sulfur and the group =N-R3; R2 and R3 each represents a member selected from the group consisting of an alkyl group containing from one to four carbon atoms and an aryl group; Z represents the nonmetallic atoms necessary to complete a heterocyclic nucleus of the type used in cyanine dyes containing from five to six atoms in the heterocyclic ring; and Q represents the nonmetallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of a 2-pyrazolin-5-one nucleus; a 2-thio-barbituric acid nucleus; and a rhodanine nucleus; (2) a water-soluble sulfonated organic compound represented by the following formula: wherein B1 represents a 1,3,5-triazin-6-ylamino group, B2 represents an aromatic group, and M represents a member selected from the group consisting of a hydrogen atom and an alkali metal atom; and (3 ) an organic reducing agent containing at least two hydroxyl group substituents selected from the class consisting of a dihydroxyarylene; a lambda -lactone; a 3-hydroxy tetronamide; a 3,4,5-trihydroxy-5,6-dihydropyronimide; and, an amino hexose reductone wherein the amino moiety of said reductone has the formula: wherein R1 and R2 are selected from the group consisting of alkyl radicals and together with the nitrogen atom the necessary atoms to form a nitrogen-containing heterocyclic radical.
 4. A photographic silver halide emulsion spectrally sensitized with a complex merocyanine dye selected from the group consisting of: 1-ethyl-4-((3-ethyl-2-benzothiazolinylidene)-ethylidene)-2-((3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)-ethylidene)-3-phenyl-5-imidazolidinone; 1,3-diethYl-5-((1-ethylnaphtho(1,2-d)thiazolin-2-ylidene)ethylidene)-2-((3 -ethyl-4-oxo-2-thioxo-5-thioxo-5-thiazolidinylidene)ethylidene)-4 -imidazolidinone; 3-ethyl-2-((1-ethylhexahydro-4,6-dioxo-2-thioxo-5-pyrimidinylidene) -ethylidene)-1-phenyl-5-((1,3,3-trimethyl-2-indolinylidene)ethylidene)-4 -imidazolidinone; 1,3-diethyl-5-((3-ethyl-2-benzothiazolinylidene)ethylidene)-2-((3-methyl-5 -oxo-1-phenyl-2-pyrazolin-4-ylidene)ethylidene)-4-imidazolidinone; 3-ethyl-5-((1-ethyl-2(1H)-B-naphthoselenazolylidene)isopropylidene)-2-(3 -ethyl-4-oxo-2-thiono-5-thiazolylidene)-4-thiazolidone; 3-ethyl-5-((3-ethyl-2-benzoxazolinylidene)ethylidene)-2-((3-ethyl-4-oxo-2 -thioxo-5-thiazolidinylidene)ethylidene)-4-thiazolidinone; 3-ethyl-5-((1-ethylnaphtho(1,2-d)thiazolin-2-zylidene)ethylidene)-2-((3 -ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)ethylidene)-1-phenyl-4 -imidazolidinone; said emulsion being supersensitized with a sulfonated triazinylstilbene and a reducing agent selected from the group consisting of a dihydroxy substituted benzene; ascorbic acid; isoascorbic acid; 5- Alpha -furyl-3,4-dihydroxy-2-imino-2, 5-dihydrofuran; 5,6-diphenyl-3,4,5-trihydroxy-5,6dihydro-pyronimide; and piperidino hexose reductone.
 5. A photographic silver halide emulsion supersensitized with the combination of 1-ethyl-4-((3-ethyl-2-benzothiazolinylidene)-ethylidene)-2-((3-ethyl-4-oxo-2-thiooxo-5-thiazolidinylidene)-ethylidene)-3-phenyl-5-imidazolidinone; ascorbic acid; and a bis(s-triazin-2-ylamino)stilbene-2,2''-disulfonic acid, sodium salt.
 6. A photographic silver halide emulsion supersensitized with the combination of 1,3-diethyl-5-((1-ethylnaphtho-(1,2-d)thiazolin-2-ylidene)ethylidene)-2-((3 -ethyl-4-oxo-2-thiooxo-5-thiazolidinylidene)ethylidene)-4-imidazolidinone; ascorbic acid; and, a bis(s-triazin-2-ylamino)stilbene-2,2''-disulfonic acid, sodium salt.
 7. A photographic silver halide emulsion supersensitized with the combination of 3-ethyl-5-((1-ethylnaphtho(1,2-d)-thiazolin-2-ylidene)ethylidene)-2-(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)ethylidene)-1-phenyl-4-imidazolidinone; ascorbic acid; and, a bis(s-triazin-2-ylamino)stilbene-2,2''-disulfonic acid, sodium salt.
 8. A photographic silver halide emulsion supersensitized with the combination of 1,3-diethyl-5-((3-ethyl-2-benzothiazolinylidene)ethylidene)-2-((3-methyl-5 -oxo-1-phenyl-2-pyrazolin-4-ylidene)ethylidene)-4-imidazolidinone; piperadino hexose reductone; and, a bis(s-triazin-2-ylamino)stilbene-2,2''-disulfonic acid, sodium salt.
 9. A photographic silver halide emulsion supersensitized with the combination of 3-ethyl-5-((1-ethylnaphtho(1,2-d)-thiazolin-2-ylidene)ethylidene)-2-(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)ethylidene)-1-phenyl-4-imidazolidinone; 5,6-di-phenyl-3,4,5-trihydroxy-5,6-dihydro pyronimide; and, a bis(s-triazin-2-ylamino)stilbene-2,2''-disulfonic acid, sodium salt. 